1. Field of the Invention
The subject invention relates to fluid filtration devices, and more particularly, to a filter assembly having a keyed lockout system to ensure replacement cartridge compatibility.
2. Background of the Related Art
Commercial vending machines for dispensing liquids such as coffee or soft drinks are wide spread in our society. It is common to filter liquids such as water in these vending machines before they are dispensed by circulating the water through an appropriate filter. It is also commonplace to find filtering devices in consumer appliances such as refrigerators for filtering drinking water and for ice production. Commercial and domestic filtering devices of this type have a limited useful life and require frequent replacement. Examples of prior art replaceable filtering devices of this type are disclosed in commonly assigned U.S. Pat. No. 4,735,716 to Petrucci et al. and U.S. Pat. No. 4,806,240 to Giordano et al.
In most instances, the replaceable filters employed in commercial and consumer appliances are manufactured in accordance with particular design specifications and performance parameters provided by the appliance manufacturer. In many cases, the filter media used in such filters consists of a proprietary material or is manufactured using a proprietary process. Thus, appliance manufactures often recommend that replacement cartridges be purchased from the original equipment provider so as to ensure the integrity and proper operation of the filtering system.
Oftentimes, the owner of a household appliance or the maintenance personnel servicing a commercial vending machine is not aware of the replacement filter specifications and operating parameters of the filtering system. Consequently, they unknowingly jeopardize the integrity of the filtration system by replacing a used filter with an inferior or incompatible replacement filter supplied by an after-market manufacturer. This problem has also been encountered by automotive filter manufacturers, as inferior replacement fuel filters are frequently installed in a vehicle without the knowledge of the vehicle owner or operator.
One solution to this problem is disclosed in U.S. Pat. No. 5,035,797 to Janik, wherein a key system is provided to ensure replacement cartridge compatibility for axially mounted fuel filters with threaded retaining collars. The key system employs a unique matrix of axially projecting keys formed in a base for axially receiving a filter cartridge, and a corresponding matrix of slots formed in a compatible cartridge, so that for a given compatible cartridge and base, the keys are interlockable in the slots to securely lock the cartridge in the base. For each non-compatible cartridge and base, the base keys are not-mateable with the cartridge slots and interfere with the mounting of the cartridge to the base. A similar key system is disclosed in U.S. Pat. No. 5,186,829 to Janik which includes a set of angularly spaced arcuate projections that protrude radially from the cylindrical side wall of the fuel filter cartridge to mate with corresponding spaced apart recesses in the base when the cartridge is axially pushed into the base. U.S. Pat. No. 5,837,137 to Janik discloses yet another key system for an axially mounted fuel filter with a threaded retaining collar.
While such prior art key systems are suitable for use in conjunction with axially mountable automotive fuel filters having threaded retaining collars, they are not easily adapted for use in conjunction with consumer and industrial water filtration systems wherein the filter cartridge is provided with a set of cam lugs configured to facilitate rotatable mounting of the cartridge to a base or supporting structure. Examples of prior art filter cartridges having lugged engagement portions are disclosed in the Petrucci et al. and Giordano et al. patents discussed hereinabove, and in U.S. Pat. Nos. 4,857,189 and 4,956,086 to Thomsen et al. It would beneficial to provide a key system for replaceable filter cartridges having lugged mounting systems.
The subject invention is directed to a unique filter assembly for ensuring replacement cartridge compatibility in filtration systems having replaceable filter cartridges with lugged mounting systems. In accordance with a preferred embodiment of the subject invention, the filter assembly comprises a cartridge member including a body portion and a cylindrical neck portion which depends from the body portion. The neck portion has a pair of diametrically opposed lugs depending radially outwardly therefrom, wherein each lug has an engagement surface defining a keyed surface formation. The neck portion has an inlet passage for delivering fluid into the body portion and an outlet passage for delivering fluid from the body portion.
The filter assembly further comprises a head member defining an axial bore and having a fluid inlet port to accommodate the ingress of fluid into the axial bore and a fluid outlet port to accommodate the egress of fluid from the axial bore. A rotary valve member is disposed within the axial bore of the head member and defines an axial bore for receiving the neck portion of the cartridge member. The axial bore of the valve member has a pair of diametrically opposed reception areas defined therein for receiving the lugs of the neck portion. Each reception area has a mating surface defining a keyed surface formation adapted and configured to mate with the keyed surface formation of a corresponding lug of a compatible filter cartridge. In addition, the valve member has an inlet orifice for communicating with the inlet port of the head member and an outlet orifice for communicating with the outlet port of the head member when the lugs of the neck portion are engaged with the reception areas of the valve member and the valve member is rotated into an operational position.
The filter assembly further comprises a support member disposed between the valve member and the cartridge member. The support member has an aperture extending therethrough for receiving and retaining the neck portion of the cartridge member and a seating area for receiving and retaining the head member. Preferably, each lug includes an inclined cam surface on a lower portion thereof for cooperating with a pair of diametrically opposed cam ramps projecting into the aperture of the support member. In use, rotation of the cartridge member relative to the support member effectuates rotational movement of the valve member relative to the head member.
In accordance with a preferred embodiment of the subject invention, the keyed surface formation on each lug includes a plurality of spaced apart tooth positions each for accommodating an axially projecting tooth, and the recessed areas include a series of spaced apart recesses for mating with the axially projecting teeth of a compatible filter cartridge. Alternative keyed surface formations and corresponding reception areas are also envisioned and are disclosed herein.
The subject invention is also directed to a filter assembly that comprises a filter cartridge including a body portion and a cylindrical neck portion depending from the body portion, wherein the neck portion has at least one lug depending radially outwardly therefrom having a keyed surface formation thereon, and a reception member defining an axial bore for receiving the neck portion of the cartridge member, the bore having at least one reception area provided therein for receiving the at least one lug, wherein the reception area has a compatible mating surface formation defined therein for engaging the keyed surface formation on the lug so as to prevent engagement with an incompatible filter cartridge. The reception member is preferably defined by a rotary valve disposed within an interior bore of a housing member or an annular insert disposed within an interior bore of a housing member.
In accordance with a preferred embodiment the subject invention, there is also disclosed a filter cartridge system that comprises a set of filter cartridges each including a cylindrical neck portion, the neck portion of each filter cartridge in the set having at least one lug depending therefrom with a keyed surface formation thereon to enable the cartridge to mate with a compatible reception member, wherein each filter cartridge in the set has a different keyed surface formation thereon.
These and other unique features of the lenticular filter cartridge assembly of the subject invention and the method of constructing the same will become more readily apparent from the following description of the drawings taken in conjunction with the detailed of the preferred embodiments.